FAQ Category: Knee

It sounds as though you have a deep cartilage tear along with your medial meniscus tear. Based on a recent review of surgical options for someone like you (a high end athlete, young, and a big chondral tear), you might look into getting an osteochondral allograft transplantation (OCA). This involves taking a size-matched piece of cartilage from a cadaver and transplanting it into your damaged knee. Rehabilitation takes about one year before you’ll be at 100% however long term studies show that it will be worth the work.

You may not be missing anything. The preventive measures you mentioned are all very important and will serve you well. According to a recent (very large) study from the Kaiser Permanent system, the overall infection rate after anterior cruciate ligament reconstruction is fairly low (0.48 per cent). That is less than one-half of one percent.

In their study of 10,626 cases treated in 41 different medical centers around the United States, there were 51 total cases of infection (superficial and deep). There was a two-to-one (2:1) ratio of deep to superficial. Superficial infections only involved the skin and occur most often in the first 30 days after ACL reconstructive surgery. Deep infections can develop months to years later and involve the deeper soft tissue structures.

Further analysis of all the data also revealed that in most cases, hamstring tendon grafts were the source of both superficial and deep infections. Staphylococcus bacteria accounted for half of the deep and three-fourths of the superficial infections. More obese patients (higher body mass index) had a greater chance of developing a superficial infection. The reason for this is unknown but may be linked with the need to remove more soft tissue in larger patients.

What is behind this observed increase in superficial and deep infections associated with hamstring tendon grafts used for ACL reconstruction? There may be more than one possible avenue for this occurrence. The authors suggest the following possibilities. Contamination may occur during the harvest procedure itself or after harvest when the tendon graft is being prepared for use.

Hamstring tendon grafts take longer to prepare giving more time for possible contamination during graft preparation. And hamstring grafts require the use of a multifilament suture, which could be the source of the bacteria. If the graft or hardware used to fix the graft in place comes in contact with the skin, then contamination is more likely. And finally, the tools (e.g., screwdriver) used to insert the screws that hold the graft in place could be an external (environmental) source of contamination.

These are all external risk factors (i.e., have nothing to do with you or your body). You may want to let your surgeon know your concerns and questions. Knowing you have a delicate immune system may be useful information when selecting graft type and performing the technical aspects of the procedure. In the meantime, keep up the good efforts to aid your immune system. It won’t hurt you and may potentially contribute to a positive outcome.

The increased risk of an infection after a hamstring autograft for the reconstruction of an anterior cruciate ligament (ACL) is a potential concern. According to a recent study, the risk of infection is 8.24 times higher for someone receiving a hamstring tendon graft compared with a bone-patellar tendon-bone (BPTB) autograft.

These are the results of a very large study from well-known and respected institution: Kaiser Permanente in California. Almost 11,000 patients from the Kaiser Permanente ACLR registry were involved in the study. These patients were treated in 41 different medical centers in six different geographical regions.

By reviewing the patient records, they were able to determine how many patients who had any kind of ACL graft surgery developed an infection afterwards.

The three main types of ACL grafts included: 1) hamstring autograft, 2) bone-patellar tendon-bone (BPTB) autograft, and 3) allograft. An autograft refers to tendon material taken from the patient and used to replace the torn ligament. An allograft is tendon graft material from a donor bank.

Although the overall infection rate was low (0.48 per cent), the fact that there was an obvious and statistically important difference between the autografts is very significant. In more simpler terms: graft choice does make a difference. There was no apparent difference in the infection rates between autografts and allografts. These findings support (agree with) other previous studies but now provide the added information of how often this happens.

Some additional details from the study also included the fact that there was a 2:1 ratio of deep (deep soft tissue or joint) to superficial (skin only) infections. The superficial infections occurred early on (first month after surgery). Deep infections were more likely to develop up to one year after the procedure.

Further analysis of all the data also revealed that in most cases, hamstring tendon grafts were the source of both superficial and deep infections. Staphylococcus bacteria accounted for half of the deep and three-fourths of the superficial infections. More obese patients (higher body mass index) had a greater chance of developing a superficial infection. The reason for this is unknown but may be linked with the need to remove more soft tissue in larger patients.

What is behind this observed increase in superficial and deep infections associated with hamstring tendon grafts used for ACL reconstruction? There may be more than one possible avenue for this occurrence. The authors suggest the following possibilities:

Ganglion cysts involving the cruciate ligaments of the knee are fairly common ranging in prevalence from 0.2 per cent up to 1.9 per cent. Men are more likely to develop this type of cyst than women but the etiology (cause) is really unknown.

There are several theories. One being that the sac holding the synovial (lubricating) fluid in the knee herniates allowing the fluid to surround the cruciate ligaments that criss-cross inside the joint. Some experts have suggested that this is a congenital problem (present at birth). The synovial cells form inside the cruciate ligaments instead of inside the synovial lining.

The most widely accepted theory is that constant stress on the cruciate ligaments causing degeneration of the mucous fluid around the ligaments results in cyst formation. Sometimes there is a previous knee injury linked with cruciate ligament ganglion cysts but not always. Whether or not injuries of the joint cartilage (meniscus or articular) have a role in cyst formation remains unknown.

Knee pain that turns out to be a proximal tibiofibular joint cyst is, indeed, fairly rare. The word proximal tells us the problem is at the knee rather than down by the ankle (since both the tibia and fibula — the bones in the lower leg — connect in both places).

A cyst is defined as an abnormal closed, bladderlike sac (membrane) containing fluid, semifluid, or semisolid matter. The fluid usually comes from a channel (pathway or connection) between the synovial fluid inside the joint and the cyst. This isn’t always the case with cysts at the proximal tibiofibular joint. The etiology (cause or reason for their formation) is not always clear. Several theories exist as to the reason why cysts of the proximal tibiofibular joint develop.

The natural history (what happens over time) for this type of cyst is a gradual increase in size over time. Left untreated, these cysts can start to put pressure on the soft tissue and nerve structures in that area. Pain that used to go away with rest becomes constant pain. Compression of the nerve and muscles can also lead to numbness, weakness, and even a condition known as foot drop (patient can no longer lift the foot properly when walking). In the worst case scenario, the cyst may hemorrhage adding insult to injury.

Recommended treatment is surgical removal of the cyst and any connection to the joint. This is best done before nerve involvement develops. Some physicians have used aspiration (withdrawing fluid from the cyst with a needle) with steroid injection. But studies show this approach has a high recurrence rate. Even with surgical removal of the cyst and its connections, there is still a high rate of recurrence. Up to one-third of all patients with this type of cyst experience another cyst forming later.

Fortunately, a tibiofibular joint cyst is fairly benign if diagnosed and treated early on (before nerve damage). Recurrence is disappointing but still treatable. Getting a second opinion is always a good idea for something as rare as a tibiofibular joint cyst. Making sure you have an accurate diagnosis is essential in planning the best treatment approach. If your diagnosis is confirmed by your outside expert, you will likely be advised to pursue surgical excision right away. Follow your physician’s advice for the best outcomes.

The failure rate for a meniscus repair is 9.8 per cent according to this study. The failure rate for a meniscal repair and ACL reconstruction is 8.2 per cent.

Depending on your age and your activities, a meniscus repair could possibly stave off osteoarthritis and buy you more time with your typical activity level. 

Once the the decision to have surgery to repair a ruptured ACL has been made, there are several factors to consider including timing of the surgery, technique used by the surgeon, and the graft site from which to build the new ACL. When making these decisions one must look at preoperative range of motion, swelling and strength as well as individual anatomy, post-operative activities and goals. For some returning to a specific sport is a priority while for others, returning to a physically active occupation is more important.

There are four typical graft options, including bone-patellar-bone autograft, hamstring tendon autograft, quadriceps tendon autograft, and allograft. MRI scans can be helpful in allowing the surgeon to determine which tendon may be most useful based on your individual physiology and the graft size. Since your goal is to return to roofing, you must take into consideration that you will be spending a lot of time in a kneeling position. For this reason, you will not want to choose the bone-patellar-bone autograft because it is associated with a higher incidence of anterior knee pain. If you are worried that a specific graft site may be more prone to reinjury, there is no research to support this idea. Graft failure rate is about 11 per cent and does not seem to be dependent of the choice of graft site. Several authors have actually reported a higher rate of ACL injury in the opposite leg compared to a reinjury of the repaired ACL. In general, those who do reinjury a repaired ACL are younger and returning to a higher level of activity.

Once you have determined that repair of your torn ACL is necessary, timing of the knee surgery is one of the first factors to consider. There is evidence supporting early surgery, as it may lead to improved functional outcomes and decreased rate of future meniscal damage. However, delayed surgery can allow for potential avoidance of surgery all together if the individual is satisfied with their knee function. In one study 50 per cent of those who opted to delay reconstructive repair of their ACL later decided to never have the surgery as they were satisfied with their functional outcomes.

There is sold evidence supporting a delay in surgery in order to reach specific preoperative strength and range of motion goals. Preoperative strength of at least 90 per cent of the quadriceps, is correlated with improved long term functional outcomes. Preoperative swelling and limitations in range of motion are correlated with increased arthrofibrosis after surgery. Thus, a preoperative rehabilitation program focusing on decreased swelling, improved range of motion and quadriceps strength is beneficial. If you can focus on preoperative rehabilitation it is safe to delay surgery.

Researchers at the University of Michigan (Ann Arbor) have performed a systematic review and meta-analysis on ways to prevent anterior cruciate ligament (ACL) injuries. This is important because so many of today’s sports injuries affect the ACL. Players can be sidelined for months (sometimes longer). In fact, it is estimated that one-quarter of a million ACL injuries occur each year in the United States.

What can be done to prevent these injuries? That is the question posed by many health care and sports professionals. Using a combined systematic review (searching the literature for all studies on the topic) and performing a meta-analysis (combining data together from many studies) is a good way to “mine the data” so-to-speak. The results of this current study provide us with evidence-based recommendations.

Before looking at the specific recommendations, it’s important to understand why these are so important. It’s not just that so many people experience ACL injuries. The fact is that many of these injuries are accompanied by damage to the surrounding tissues as well.

The result is a weak knee that is at risk for future injuries and even the development of early arthritis. Preventing ACL injuries not only protects people from pain and suffering, it can also protect the pocket book for the individual and for society.

Presently, there is a wide range of risk factors that might contribute to ACL injuries. Addressing any of these factors that can be modified (changed) may provide some protection. For example, muscular strength, alignment, and flexibility are modifiable factors. The use of high-risk positions and/or techniques during sports play and lack of aerobic conditioning are additional modifiable factors that can be analyzed and modified.

Improving any one or all of these features may reduce the anatomic risk of ACL injuries. Age, genetics, and hormonal factors are nonmodifiable and may contribute to ACL injuries but cannot be changed to reduce the risk of knee injury.

Risk factors outside of the human body but still within our control are referred to as environmental factors. These include playing surface, use of footwear and/or braces, playing outside in bad weather.

The majority of evidence supported two directions for prevention of ACL injuries: neuromuscular re-education and educational interventions. It turns out that training programs to address the anatomic risk factors do, indeed, reduce the risk of ACL injuries by as much as 50 per cent.

Strategies used successfully include core training and stretching to improve hamstring flexibility. Training to improve balance, movement, and speed are also important. Programs that include esistance training and neuromuscular re-education through the use of plyometrics, weight training, and aerobic conditioning are also helpful.

Since the studies available did not analyze individual parts of training programs, this systematic review/meta-analysis was unable to pinpoint exactly which training interventions work the best. It does appear that more time spent in training and following the exercise programs carefully (compliance) provide a direct protective effect.

The authors of this study suggest future studies need to be done that make comparisons between specific groups and specific prevention interventions. Comparing one treatment against no treatment is not as helpful in determining the best prevention approach as comparing one intervention to another.

With more and more adults getting knee replacements, analysts are taking a closer look at the costs versus benefits to the individual patient and to society. Society can include employers and insurance providers (payers). You are a part of “society” in this sense if you pay taxes that finance Medicare, a principal payer of many surgical procedures in older adults.

There are three ways to evaluate the “cost” of surgical versus conservative care for knee osteoarthritis: 1) direct costs, 2) indirect costs, and 3) quality of life measures. Direct costs include any and all medical expenses for any treatment provided.

Indirect costs refer to lost wages when the patient can no longer work full-time or can’t work at all and to disability payments paid out over time. Indirect costs to the employer occur due to employee absenteeism and lost productivity. Quality of life is measured based on patients’ perception of pain, motion (loss of motion), function (loss of function), and level of disability.

A recent study performed by an independent agency took a closer look at all costs associated with knee replacement versus conservative care (without surgery) for patients with end-stage (severe) osteoarthritis. They studied the U.S. population (ages 40 and older) who received a total knee replacement in the year 2009.

After reviewing and analyzing all the data collected, the research showed that there was a 12 billion dollar savings to society in one year (2009) for the 600,000 total knee replacements that were done. They concluded this represents a significant amount of money attributed to extra work years (and increased income) made possible by the surgery.

This information will be very helpful if and when insurance companies and other third party payers suggest finding ways to limit who qualifies for a total knee replacement (referred to as coverage restrictions). Likewise, if higher copayments are proposed, research like this comparing costs and estimating savings to society is very important.

Older adults like your grandparents had higher total medical costs regardless of whether they had surgery or were treated conservatively. But the cost of a total knee replacement for severe, limiting osteoarthritis in the older group was also offset by fewer health problems (heart attacks, strokes) compared with patients of the same age with equal joint disease who did not have knee replacement surgery.

The researchers concluded that total knee replacements are cost-effective when viewed from a societal perspective. This study showed a positive net benefit to society in terms of cost savings for all age groups but especially those younger than 70 years old (and especially for adults in their early 40s).

Quality of life is improved with surgery, which can also translate into dollars saved. This is the area most likely to make a difference for your older family members. Although improvement in quality of life is greater among younger patients, the net gain in older adults when translated into dollars and cents was still impressive. Payers and policy makers will likely take this information into consideration when making plans to restrict access to knee replacement surgery.

There are three ways to evaluate the “cost” of surgical versus conservative care for knee osteoarthritis: 1) direct costs, 2) indirect costs, and 3) quality of life measures. Direct costs include any and all medical expenses for any treatment (surgical or nonsurgical) provided.

Indirect costs refer to lost wages when the patient can no longer work full-time or can’t work at all and to disability payments paid out over time. Indirect costs to the employer occur due to employee absenteeism and lost productivity. Quality of life is measured based on patients’ perception of pain, motion (loss of motion), function (loss of function), and level of disability.

Research shows that there was a 12 billion dollar savings to society in one year (2009) for the 600,000 total knee replacements that were done in that year. They concluded this represents a significant amount of money attributed to extra work years (and increased income) made possible by the surgery.

Factors affecting lifetime savings associated with total knee replacements include age and work status. Younger patients have longer to work and earn money. The study showed that patients in the youngest category (40 to 44 years old) could potentially (each) earn $174,364 more over a lifetime by having the surgery compared with the over 80 age group.

Older adults also had higher total medical costs regardless of whether they had surgery or were treated conservatively. But the cost of a total knee replacement for severe, limiting osteoarthritis in the older group was also offset by fewer health problems (heart attacks, strokes) compared with patients of the same age with equal joint disease who did not have knee replacement surgery.

In a parallel analysis, work status (receiving disability, retired, or working part- or full-time) was equally important in calculating cost to society. As you might expect, those individuals who continue working and earning income generate greater savings compared with patients who receive disability checks each month.

You won’t necessarily receive a check that equals the amount of indirect costs saved by having a knee replacement. But your ability to keep working and your value to your employer in terms of productivity will bring you benefits that have a direct and indirect monetary value. Improved quality of life is another value added that can be measured as an benefit that reduces the cost of the procedure when measured by research analysts.

You are asking about something physicians refer to as the natural history of an injury. In other words, what happens over time? In your case, the question is what is the natural history of an injury to the posterior cruciate ligament (PCL) when treatment is conservative care?

Currently, surgeons are doing more surgeries to restore normal PCL stability but there is insufficient evidence to support this treatment approach. This is especially true when the PCL is the only structure involved (i.e., no other soft tissue injuries are present). There is interest among orthopedic surgeons in knowing if non-surgical treatment for PCL injuries has a higher rate of osteoarthritis later in life. A second question is whether surgery to reconstruct the PCL yields better results (possibly even preventing osteoarthritis).

There are only a handful of long-term studies that might give us some clues but they do offer some interesting information. For example, recent long-term results of nonoperative treatment of PCL injuries were published from the Shelbourne Knee Center in Indiana. The patients were followed a minimum of 10 years after the injury (up to 21 years for some patients).

Everyone in the study had been in a previous study by the same authors. This report is from ongoing follow-up with these same patients who were treated for their isolated PCL injury with a home rehabilitation (exercise) program.

X-rays were used to look for signs of osteoarthritis (e.g., swelling, joint space narrowing, bone spurs). Leg strength, grade (severity) of PCL laxity (looseness), knee range-of-motion, and function were also assessed at each point of follow-up. All measurements were compared with the patient’s other (uninjured) knee.

As it turned out, there wasn’t a higher rate of osteoarthritis (OA) following nonoperative treatment of isolated PCL tears. Patients who had any OA had the same amount from side to side. This suggests that regardless of the PCL injury, they would have developed some (mild to moderate) OA over time. In fact, some of the patients who did have surgery to reconstruct the PCL had worse OA compared with patients who had the conservative care.

The authors concluded that “if PCL reconstruction is being performed to prevent OA, this goal has not been met.” The amount of knee arthritis that develops years after an isolated PCL injury is actually very low. They recommend caution in doing surgery to reconstruct PCL injuries — even when patients are having acute flare-ups of painful symptoms.

Other studies show that whereas PCL surgery can improve knee joint stability, the PCL is not returned to “normal.” Complications of surgery for PCL injuries include knee stiffness, loss of knee motion, infection, and problems with hardware. As the patients in the study just mentioned demonstrated, full knee motion, good muscle strength, and good function can be achieved with a nonoperative approach to this problem. It is also very possible to remain active (even in sports requiring jumping and pivoting) years after the initial injury without surgery.

It might be helpful to know how much arthritis is present in your other knee to compare it to the knee in question. It’s possible that although you have painful symptoms in your previously injured knee, the cause may not be the arthritic changes seen on an X-ray.

Muscle weakness, postural alignment, and/or altered knee proprioception (joint sense of position) could actually be contributing to your symptoms. Likewise, a problem at the hip can be referred to the knee on the same side. A thorough examination may be needed to sort out all the possible causes for your knee pain. A short-term strengthening/rehab program may be all you need at this time.

The posterior cruciate ligament (PCL) is one of two ligaments that criss-cross inside the knee joint to hold the two leg bones (femur and tibia) together. The second (more commonly injured) ligament is the anterior cruciate ligament (ACL). These two ligaments provide stability to the knee joint while still allowing motion.

Results of nonoperative treatment of PCL injuries is the subject of a long-term study recently reported from the Shelbourne Knee Center in Indiana. This is one of only a handful of studies following patients with acute, isolated PCL ruptures. And it is unique in that the patients were followed a minimum of 10 years after the injury (up to 21 years for some patients).

Everyone in the study had been in a previous study by the same authors. This report is from ongoing follow-up with these same patients who were treated for their isolated PCL injury with a home rehabilitation (exercise) program. The difference between you and these patients is that they started the rehab program within 30 days of the injury. Recent studies of patients with “old” (chronic) injuries pursuing a rehab program much later are not availabler. The information provided by this particular study may still be useful to you in discussing your situation with your physician.

X-rays were used to look for signs of osteoarthritis (e.g., swelling, joint space narrowing, bone spurs). Leg strength, grade (severity) of PCL laxity (looseness), knee range-of-motion, and function were also assessed at each point of follow-up. All measurements were compared with the patient’s other (uninjured) knee.

As it turned out, there wasn’t a higher rate of osteoarthritis (OA) following nonoperative treatment of isolated PCL tears. Patients who had any OA had the same amount from side to side. This suggests that regardless of the PCL injury, they would have developed some (mild to moderate) OA over time. In fact, some of the patients who did have surgery to reconstruct the PCL had worse OA compared with patients who had the conservative care.

The authors concluded that “if PCL reconstruction is being performed to prevent OA, this goal has not been met.” The amount of knee arthritis that develops years after an isolated PCL injury is actually very low. They recommend caution in doing surgery to reconstruct PCL injuries — even when patients are having acute flare-ups of painful symptoms (which is what you are experiencing).

Other studies show that whereas PCL surgery can improve knee joint stability, the PCL is not returned to “normal.” Complications of surgery for PCL injuries include knee stiffness, loss of knee motion, infection, and problems with hardware. As the patients in this study demonstrated, full knee motion, good muscle strength, and good function can be achieved with a nonoperative approach to this problem. It is also very possible to remain active (even in sports requiring jumping and pivoting) years after the initial injury without surgery.

You can talk to your physician about seeing a physical therapist or you can refer yourself directly. a Six to 12 week exercise program designed for your specific needs will give you an idea whether or not rehab is beneficial. Given your interest in staying active, it may help in other areas as well.

As you point out, the proposed advantages of the simultaneous bilateral knee replacements are decreased costs and shorter recovery time. Previous studies have reported more complications with simultaneous knee replacements compared with staged procedures. Problems such as gastrointestinal complications, blood clots, heart attacks, and even death can occur.

A recent high-quality study has some information that may be helpful to you. Researchers at the University of North Carolina (Charlotte) and the OrthoCarolina Research Institute (also in Charlotte, North Carolina) took on the task of doing a cost-utility and cost-effectiveness study. They used the Nationwide Inpatient Sample data to compare the results of 24,574 cases of simultaneous knee replacements with 382,496 patients who had unilateral (one-at-a-time) procedures.

They found no difference in the overall rate of complications between these two approaches. In fact, for minor, major and in-hospital mortality (death), simultaneous procedures had lover complication rates. For example, the major complication rate for the staged group was 2.36 per cent compared with 1.49 per cent among the simultaneous group. The minor complication rate was 8.98 per cent (staged group) versus 6.84 per cent (simultaneous group). The number of in-hospital deaths was slightly higher in the simultaneous group (0.2 per cent versus 0.18 per cent for staged bilateral total knee replacements).

Measures used to compare the outcomes included perioperative complications (minor, major, and mortality), hospital costs, rehabilitation costs, anesthesia costs, and health utilities (visits to the surgeon, primary care physician, physical therapist). Most striking was the difference in overall costs: $43,401 for simultaneous procedures compared to $72,233 for staged procedures (almost double).

The researchers concluded that the results (or outcomes) were just as good between the staged (one-at-a-time) approach and the simultaneous (both done together) method.
This cost analysis showed the economic benefit of simultaneous procedures. Replacing both knee joints at the same time was determined to be both safe and effective.

Although there is a risk of increased complications with simultaneous procedures, exposure to only one anesthetic, decreased recovery time, shorter hospital stay, and lower costs may outweigh the risk. Older adults with serious health problems may not qualify as candidates for the simultaneous replacement of both knees.

Like you, many patients with painful arthritic knees wrestle with the decision to have them replaced one at a time (two separate surgeries and rehab) or both at the same time. The proposed advantages of the simultaneous bilateral knee replacements are decreased costs and shorter recovery time.

Some people make the decision simply based on economics (i.e., based on the amount of any out-of-pocket expense between the two procedures). A recent study showed that the difference in overall costs is significant: $43,401 for simultaneous procedures compared to $72,233 for staged procedures (almost double). This can add up to quite a bit of difference in out-of-pocket expenses.

You may find the results of a recent study of interest. Researchers at the University of North Carolina (Charlotte) and the OrthoCarolina Research Institute (also in Charlotte, North Carolina) took on the task of doing a cost-utility and cost-effectiveness study. They used the Nationwide Inpatient Sample data to compare the results of 24,574 cases of simultaneous knee replacements with 382,496 patients who had unilateral (one-at-a-time) procedures.

Measures used to compare the outcomes included perioperative complications (minor, major, and mortality), hospital costs, rehabilitation costs, anesthesia costs, and health utilities (visits to the surgeon, primary care physician, physical therapist). The results (or outcomes) were just as good between the staged (one-at-a-time) approach and the simultaneous (both done together) method.

Previous studies have reported more complications with simultaneous knee replacements compared with staged procedures. Problems such as gastrointestinal complications, blood clots, heart attacks, and even death can occur. But this study found no difference in the overall rate of complications between these two approaches.

In fact, for minor, major and in-hospital mortality (death), simultaneous procedures had lover complication rates. For example, the major complication rate for the staged group was 2.36 per cent compared with 1.49 per cent among the simultaneous group. The minor complication rate was 8.98 per cent (staged group) versus 6.84 per cent (simultaneous group).

This cost analysis showed the economic benefit of simultaneous procedures. Replacing both knee joints at the same time is both safe and effective. Data analyzed provides quality comparative evidence that can guide physicians and patients when faced with this decision.

Although there is a risk of increased complications with simultaneous procedures, exposure to only one anesthetic, decreased recovery time, shorter hospital stay, and lower costs may outweigh the risk. Older adults with serious health problems may not qualify as candidates for the simultaneous replacement of both knees. Your surgeon will make this assessment and advise you as to whether or not you qualify for simultaneous replacements. You will want to discuss this decision with him or her as there can be other considerations in each individual case.

It is estimated that one-quarter of a million ACL injuries occur each year in the United States. As you know, players can be sidelined for months (sometimes longer). This is a concern to many people at all levels from high school to professional sports.

Preventing ACL injuries not only protects people from pain and suffering, it can also protect the pocketbook for the individual and for society. The fact is that many of these injuries are accompanied by damage to the surrounding tissues as well. The result is a weak knee that is at risk for future injuries and even the development of early arthritis.

Researchers at the University of Michigan (Ann Arbor) have performed a systematic review and meta-analysis on ways to prevent anterior cruciate ligament (ACL) injuries. They have confirmed that there is evidence to support the use of neuromuscular training programs — enough evidence to give this approach a second look.

Presently, there is a wide range of risk factors that might contribute to ACL injuries. Addressing any of these factors that can be modified (changed) may provide some protection. For example, muscular strength, alignment, and flexibility are modifiable factors. The use of high-risk positions and/or techniques during sports play and lack of aerobic conditioning are additional modifiable factors that can be analyzed and modified.

Improving any one or all of these features may reduce the anatomic risk of ACL injuries. Age, genetics, and hormonal factors are nonmodifiable and may contribute to ACL injuries but cannot be changed to reduce the risk of knee injury.

Risk factors outside of the human body but still within our control are referred to as environmental factors. These include playing surface, use of footwear and/or braces, playing outside in bad weather.

The majority of evidence supported two directions for prevention of ACL injuries: neuromuscular re-education and educational interventions. Neuromuscular re-education includes addressing muscular strength, proprioception (joint perception of position), postural alignment, knee and ankle stability, foot position, core strength, and flexibility.

It turns out that training programs to address the anatomic risk factors do, indeed, reduce the risk of ACL injuries by as much as 50 per cent. Since the studies available did not analyze individual parts of training programs, this systematic review/meta-analysis was unable to pinpoint exactly which training interventions work the best. It does appear that more time spent in training and following the exercise programs carefully (compliance) provide a direct protective effect.

In a recent study, orthopedic surgeons from the United Kingdom proved for themselves that cementless unicompartmental knee replacements are as good (if not better) than cemented implants of the same type.

They compared two groups of patients: 32 who received the cemented Oxford unicompartmental knee replacement and 30 others who were implanted with the cementless Oxford device. All of the procedures were done using a minimally invasive surgical technique.

Participants in the study were followed for five years using fluoroscopic (real-time) X-rays. The advantage of this type of imaging study is that the X-ray beam can be focused on the underside of the implant. This gives the surgeon a better view of the bone-to-implant interface (where the implant sits against the bone). This type of imaging study is helpful since the most common cause of revision surgery after unicompartmental knee replacement is loosening of the implant without infection (called aseptic loosening).

Other measures of outcome included functional and activity scores on three valid, reliable tools: the Oxford Knee Score, the Tegner Activity Score, and the Knee Society Scores. These questionnaires are filled out by the patient providing information about symptoms (pain, swelling, clicking, locking, knee giving out), function (ability to kneel, squat, stand up from a chair, go up and down stairs), and activities of daily living (shopping, cooking, bathing, driving).

The results were so positive for the cementless version, they say that they only use this type of implant now when unicompartmental replacement is needed. In fact, they have already studied 1,000 patients for a year who received the Oxford cementless unicompartmental knee replacement. Results of that study will be published in the near future.

Results showed that after five years, there was no significant difference between the two groups based on most of the functional outcome measures. Overall, everyone in both groups improved significantly from before surgery to after surgery. The major difference of note was seen in the X-rays.

The cementless group had better fixation with fewer cases of aseptic (without infection) loosening. The end-result was fewer revision surgeries for the cementless group. In fact, even the cementless implants that were not placed with perfect alignment were still in place and working well without symptoms or problems for the affected patients.

The surgeons concluded that the use of the cementless unicompartmental knee replacement has a lower failure rate compared with the cemented version of this implant. They pointed out the advantages of the cementless device as: 1) shorter surgical time, 2) simpler surgical procedure, 3) more forgiving when a less than optimal position of the implant is achieved, and 4) no complications caused by cement.

Problems associated with cemented implants (from the cement itself) include tightening tissues from excess cement oozing into the nearby soft tissue structures, loose fragments of cement causing pain and mechanical problems, and excess wear and failure of components requiring additional surgery. These observations and the better results for the cementless group provide the evidence needed for many surgeons to shift to the use of cementless fixation for unicompartmental knee replacements.

Patients most likely to receive a unicompartmental knee replacement have osteoarthritis that is painful and severe affecting the front and inner half (side closest to the other knee). This would be labeled end-stage osteoarthritis.

Diagnostic examination of the knee joint would show full-thickness loss of cartilage in the medial compartment but full thickness cartilage in the lateral compartment. The lateral compartment is the section of the joint on the side away from the other knee.

Other criteria for unicompartmental knee replacement include: 1) the patient has an intact and fully functioning anterior cruciate ligament (ACL) and 2) medial collateral ligament (also along the inside of the knee joint). These two ligaments provide stability while still allowing smooth motion of the joint.

There is evidence that cementless unicompartmental knee replacements are as good (if not better) than cemented implants of the same type. What makes the cementless implant better than the cemented device? And how do we know this is true? These are the two questions the researchers addressed in a study from the United Kingdom.

They compared two groups of patients: 32 who received the cemented Oxford unicompartmental knee replacement and 30 others who were implanted with the cementless Oxford device. All of the procedures were done using a minimally invasive surgical technique.

Participants in the study were followed for five years using fluoroscopic (real-time) X-rays. The advantage of this type of imaging study is that the X-ray beam can be focused on the underside of the implant. This gives the surgeon a better view of the bone-to-implant interface (where the implant sits against the bone). This type of imaging study is helpful since the most common cause of revision surgery after unicompartmental knee replacement is loosening of the implant without infection (called aseptic loosening).

Results showed that after five years, the cementless group had better fixation with fewer cases of aseptic (without infection) loosening. The end-result was fewer revision surgeries for the cementless group. In fact, even the cementless implants that were not placed with perfect alignment were still in place and working well without symptoms or problems for the affected patients.

The authors concluded that the use of the cementless unicompartmental knee replacement has a lower failure rate compared with the cemented version of this implant. They pointed out these advantages of the cementless device: 1) shorter surgical time, 2) simpler surgical procedure, 3) more forgiving when a less than optimal position of the implant is achieved, and 4) no complications caused by cement.

Problems associated with cemented implants (from the cement itself) include tightening tissues from excess cement oozing into the nearby soft tissue structures, loose fragments of cement causing pain and mechanical problems, and excess wear and failure of components requiring additional surgery. These observations and the better results for the cementless group provide the evidence needed for surgeons to use cementless fixation for unicompartmental knee replacements.

Most people who have surgery to reconstruct a ruptured anterior cruciate ligament (ACL) expect that procedure to be the only one they have done on the knee. But unfortunately, there is a group of patients who end up needing a second knee surgery — and even sometimes surgery on the other leg. How can you tell if this scenario might happen to you?

An investigation performed at the Vanderbilt University Medical Center in Nashville, Tennessee may shed some light on both the rate of second surgeries and the risk factors (or “predictors”) for subsequent surgeries. With as many as 200,000 ACL surgeries done each year in the United States, surgeons and patients alike may benefit from the information this study provided.

They followed almost 1,000 patients over a period of six years after ACL reconstructive surgery on one leg. They found a surprising number of patients required additional knee surgery on the same leg that had the first ACL reconstruction (18.9 per cent). That is almost one out of every five patients. And another 10 per cent (one out of every 10 patients) later had surgery on the other knee.

What happened that these patients required further procedures and why? Analysis of the data revealed what you have heard: that younger patients (younger than 18 years) were more likely to need further surgery. Younger patients with a ruptured ACL may just be more active putting them at increased risk of further problems. Or they may not follow the physician’s and physical therapist’s instructions after surgery. This type of noncompliance could be a factor but was not determined in this study.

One other patient-related factor was mentioned but not studied: the potential for reinjury based on genetic features such as collagen disruption affecting both ligaments and cartilage. A third risk factor (predictor) was the use of an allograft (from a donor rather than from the patient) to reconstruct the damaged ACL. This factor falls under the category of surgical technique (rather than being a patient-related factor).

The authors questioned whether being overweight or female might be other risk factors or predictors of subsequent knee surgeries. But this was not the case in this study. Other studies have reported higher reoperation rates among females. In general, the overall evidence does not show a difference in male versus female reoperation rates.